Prince testified his dad was amped over the "This Is It" tour but felt he needed more time to rehearse. Apparently, AEG and MJ got into it during phone conversations and the calls made Michael break down in tears.

Prince also testified AEG honcho Randy Phillips came over to the house several times and he saw Phillips aggressively grab Dr. Conrad Murray by the elbow, as if to school him.

Prince got personal and talked about how involved Michael was in his kids' lives -- something that's highly relevant in a wrongful death case in assessing damages. He told the jury about how MJ loved home videos -- one showing Prince on a little car as Paris talked into a mic while "Daddy's Home" (a Jackson 5 song) played in the background.

Prince also said the day MJ went into full cardiac arrest at his home, Paris was screaming that she wanted her daddy. Prince says Dr. Murray announced at the house that MJ was dead from a heart attack.

The point of the testimony -- lawyers for the Jackson family are trying to prove AEG pushed Michael mercilessly and that, combined with Murray's bad medicine, cost MJ his life.